Immunoprecipitation of D^VICe and D^VIcE proteins followed by immunoblot analysis of immune complexes with rabbit sera reactive to the fourth external and C-terminal domains of Rh polypeptides. Immunoprecipitation was performed as described in Materials and Methods, and the resultant immune complexes were separated by SDS-PAGE on 10% (wt/vol) polyacrylamide gels. Blotted membranes were then incubated with either anti-Cter or anti-loop 4e serum, and this is indicated below each panel. The position of the Rh proteins (M_r 30-32,000) is indicated in the central panel between the two blots. Control blotting samples of erythrocyte membranes are shown on the left of each immunoblot.